The present invention relates to an arc discharge preventing device, which is installed between a battery and a DC/DC converter which are mounted on a moving body, such as a vehicle.
A vehicle as a moving body is installed with bus bars contained in electrical connection boxes, such as junction boxes, relay boxes and fuse boxes, electrical connection terminals, and many power transmission lines for transmitting electric powers and signals.
Generally, in general passenger vehicles, voltage of electric power transmitted through the power transmission line is 14V (effective voltage), and in large vehicles, such as buses and tracks, the power voltage is 28V (effective voltage) (=14xc3x972). Particularly, in large vehicles, there is an approach of using the power supply system capable of supplying electric powers of multiple voltages, not the single voltage, under the requirements of improving the driving efficiency of the loads and securing the optimum efficiency of each load. Further, in the electric cars and fuel cell vehicles, there is an approach of using the power supply system capable of supplying electric powers of multiple voltages, not the single voltage, under the requirements of improving the driving efficiency of the loads and securing the optimum efficiency of each load.
More exactly, the most practical way under consideration is to employ a power supply system in which a power voltage is 14V (effective voltage) as in the related case, and a high power voltage is 42V (effective voltage) as the maximum voltage which does not require great alteration of the transmission system specifications.
An example of a power supply system 101 capable of supplying electric powers of multiple of voltages is shown in FIG. 13. The power supply system 101 uses a high voltage battery 102 as a main power source. The high voltage battery 102 supplies electric power to a high voltage load 103 which needs high voltage power. The power source system 101 includes a DC/DC converter 104 for converting electric power of 42V to electric power of 14V. The DC/DC converter 104 is connected to a low voltage load 105 which requires electric power of low voltage. The high voltage battery 102, the high voltage load 103, the DC/DC converter 104 and the low voltage load 105 form electronic devices, respectively.
In the power source system 101, when the loads 103, 105 are operated, in particular when an electric wire is connected to or disconnected from the terminal of the high voltage battery 102, arc discharge often occurs at, for example, a connection part between the terminal and the electric wire.
If the DC/DC converter 104 is once operated, charge is stored in the capacitors or the like in the DC/DC converter 104. As a status of the high voltage battery 102 is closer to an empty state, there is an increased chance that the arc discharge occurs at the connection part between the terminal and the electric wire or the like when the electric wire is connected to the terminal of the high voltage battery 102.
If the DC/DC converter 104 is left not operated for a long period, the charge stored in the capacitor contained in the DC/DC converter is gradually discharged. In this case, as the status of the high voltage battery 102 is closer to the full charged state, there is an increased chance that the arc discharge occurs at the connection part between the terminal and the electric wire or the like when the electric wire is connected to the terminal of the high voltage battery 102, increases. Thus, in the power source system 101, there is a fear that the arc discharge occurs when the electronic devices are electrically connected or the electrically interconnected electronic devices are disconnected one from the other.
It is therefore an object of the present invention to provide an arc discharge preventing device, which is capable of preventing the arc discharge from occurring when the electronic devices are electrically interconnected or the electrically interconnected electronic devices are disconnected one from the other.
In order to achieve the above object, according to the present invention, there is provided an arc discharge preventing device, which is electrically connected to at least two electronic devices, the arc discharge preventing device, comprising:
an insulating main body;
a first terminal, provided on the insulating main body, and electrically connected to a first electronic device;
a second terminal, provided on the insulating main body, and electrically connected to a second electronic device;
a low conductive member, provided on the insulating main body, and having a first resistance value, the low conductive member being electrically connected to the first and second terminals; and
a conductive member, detachably mounted on the insulating main body, and having a second resistance value lower than the first resistance value, the conductive member being electrically connected to the first and second terminals when the conductive member is attached to the insulating main body.
In the above configuration, the first terminal is connected to a first electronic device, the second terminal is connected to the second electronic device, and in this connection state, electric power is made to flow through a path between the electronic devices. At this time, the electric power flows mainly through a conductive member in the path between the electronic devices. Accordingly, if the conductive member is attached to the main body part, the electric power may be made to flow through the path between the electronic devices.
The conductive member is removed from the main body in a state that the first terminal is connected to the first electronic device, the second terminal is connected to the second electronic device, and electric power is made to flow through a path between the electronic devices. In this state, the electric power which flows through the path between the electronic devices flows through the low conductive member. A current value of the electric power flowing through the path between the electronic devices is small. Accordingly, no arc discharge occurs when the electrical wire is removed from the terminal of the electronic device. Further, no arc discharge occurs even when another conductive member comes in contact with the terminal of the electronic device.
One of the first and second terminals is connected to a DC/DC converter as an electronic device, and a conductive member is connected to another electronic device. In a state that the conductive member is connected to the main body, the DC/DC converter is operated even once. When the conductive member is removed from the main body, charge stored in the DC/DC converter flows therefrom through the low conductive member. Accordingly, a current value of the electric power flowing through the path between the DC/DC converter 9 and another electronic device is small. No arc discharge occurs when the electrical wires are removed from the terminals of the DC/DC converter and others. No arc discharge occurs even if another conductive member comes in contact with the terminals of the DC/DC converter and others.
One of the first and second terminals is connected to the DC/DC converter as is left not operated for a long time in a state that the conductive member is removed from the main body part, and the other terminal is connected to a battery as an electronic device. In this connection state, the electric power supplied from the battery flows through the low conductive member to the DC/DC converter. Accordingly, a current value of the electric power flowing between the battery and the DC/DC converter is small.
Therefore, no arc discharge occurs when the terminal of the DC/DC converter is connected to the one terminal or when the battery terminal is connected to the other terminal. No arc discharge occurs when the electronic devices are interconnected or when the interconnected electronic devices are disconnected one from the other. In the arc discharge preventing device as broadly defined, the first terminal is connected to one of the electronic devices, the second terminal is connected to the other of the electronic devices, and in this connection state, electric power is made to flow through a path between the electronic devices. At this time, the electric power flows mainly through the conductive member, between the electronic devices. Accordingly, if the conductive member is attached to the main body, the electric power may be made to flow through the path between the electronic devices.
Preferably, the arc discharge preventing device further comprises an insulating second main body, detachably mounted on the main body, and on which the conductive member is mounted. The second main body is provided with a covering parts, which covers the first and second terminals in cooperation with the main body when the second main body is attached to the insulating main body so as to electrically connected the conductive member and the first and second terminals.
In the above configuration, the second main body includes covering parts. With provision of the second main body, in a state that the conductive member is electrically connected to the first and second terminals, another conductive member never comes in contact with those terminals. This feature eliminates a chance that when the electric power is flowing through the conductive member between the terminals, another conductive member comes in contact with those terminals. No arc discharge occurs at those terminals and the another conductive member when the electronic devices are electrically interconnected, or when those electronic devices electrically interconnected are disconnected one from the other.